Marketing and pricing? I don't know..

Maybe it's because of the XBO. Everyone saw it and then said, "360, here I come!"

...Or it could just be marketing... and how cheap it is compared to other consoles. (Like the next-gen ones.)

It's the one strong market they have, the U.S. has responded well to them. Fps's are the prevalent genre here, so that certainly helps.

Inertia.

because it has the best online features . I like the 360, because it is easy to chat with my friend regardless of what game they are playing.

The casuals eat up that 4GB garbage.

'Murica.

Cheap and good library of games. The 4GB version goes on sale for $100 - $150 from time to time.

Price. Nothing more really.

They followed Don's advice.